#!/bin/sh
# Solarize the terminal

# Useful terminal control sequences:
#
# Sequence  Abbrev  Description
# -----     -----   -----------------------------
# ESC P     DCS     Device Control String
# ESC [     CSI     Control Sequence Introducer
# ESC \     ST      String Terminator
# ESC ]     OSC     Operating System Control
#
#
# More info at:
#   * https://www.xfree86.org/4.8.0/ctlseqs.html
#   * https://vt100.net/
#   * https://iterm2.com/utilities/imgcat

# In tmux, OSC sequences can be forwarded to the underlying terminal by:
#   * Wrapping the sequence with `DCS tmux; <sequence> ST`
#   * Replacing ESC in <sequence> with ESC ESC.
# Either ST or BEL (\a) can be used to end an OSC sequence. However, tmux
# requires ST to end its wrapping DCS.
if [ -n "$TMUX" ]; then
    OSC=$(printf '\ePtmux;\e\e]')
    ST=$(printf '\a\e\\')
else
    OSC=$(printf '\e]')
    ST=$(printf '\a')
fi

# Color definitions (from http://ethanschoonover.com/solarized)
 Base03="002B36"  Base02="073642"  Base01="586E75"  Base00="657B83"
  Base0="839496"   Base1="93A1A1"   Base2="EEE8D5"  Base3="FDF6E3"
    Red="DC322F"  Orange="CB4B16"  Yellow="B58900"  Green="859900"
   Cyan="2AA198"    Blue="268BD2"  Violet="6C71C4"  Magenta="D33682"

# Documentation for iTerm2 at
# https://iterm2.com/documentation-escape-codes.html
# under the heading "Change the color palette".
set_iterm2_colors() {  # 1: foreground, 2: background, 3: cursor
    while read -r key rgb; do
        printf "%s1337;SetColors=%s=%s%s" "$OSC" "$key" "$rgb" "$ST"
    done <<EOF
        black       $Base02
        red         $Red
        green       $Green
        yellow      $Yellow
        blue        $Blue
        magenta     $Magenta
        cyan        $Cyan
        white       $Base2
        br_black    $Base03
        br_red      $Orange
        br_green    $Base01
        br_yellow   $Base00
        br_blue     $Base0
        br_magenta  $Violet
        br_cyan     $Base1
        br_white    $Base3
        fg          $1
        bg          $2
        bold        $1
        selfg       $Base2
        selbg       $Base01
        curfg       $3
        curbg       $3
        link        $Cyan
EOF
    printf "%s1337;CursorShape=2%s" "$OSC" "$ST"  # set cursor shape to underline
}

# Documentation for xterm at https://www.xfree86.org/4.8.0/ctlseqs.html
# under the heading "Operating System Controls".
set_xterm_colors() {    # $1 foreground, $2 background, $3 cursor
    # Send sequence OSC Ps BEL
    # where Ps   -> 4;c;spec
    #       c    -> index of the ANSI color to change [0..15]
    #       spec -> RGB value of color as rgb:RR/GG/BB
    awk -v osc="$OSC" -v st="$ST" -v ORS="" \
        '{print osc "4;" $1 ";rgb:" substr($2,1,2) "/" substr($2,3,2) "/" substr($2,5,2) st}' \
        <<EOF
        0  $Base02
        1  $Red
        2  $Green
        3  $Yellow
        4  $Blue
        5  $Magenta
        6  $Cyan
        7  $Base2
        8  $Base03
        9  $Orange
        10 $Base01
        11 $Base00
        12 $Base0
        13 $Violet
        14 $Base1
        15 $Base3
EOF
    # Send sequence OSC Ps ; Pt BEL
    # where Ps -> foreground (10), background (11), or cursor (12)
    #       Pt -> RGB value of color as rgb:RR/GG/BB
    awk -v osc="$OSC" -v st="$ST" -v ORS="" \
        '{print osc $1 ";rgb:" substr($2,1,2) "/" substr($2,3,2) "/" substr($2,5,2) st}' \
        <<EOF
        10 $1
        11 $2
        12 $3
EOF
}

set_terminal_colors() {  # 1: foreground, 2: background, 3: cursor
    if [ -n "$ITERM_SESSION_ID" ]; then
        set_iterm2_colors "$1" "$2" "$3"  # iTerm2
    else
        set_xterm_colors "$1" "$2" "$3"  # assume xterm
    fi
}

main() {
    if [ "${BACKGROUND:-dark}" = "light" ]; then
        set_terminal_colors $Base01 $Base3 $Red    # fg bg cursor
    else
        set_terminal_colors $Base1 $Base03 $Red    # fg bg cursor
    fi

    if [ -n "$TMUX" ] && [ -f "$XDG_CONFIG_HOME/tmux/tmux-colors.conf" ]; then
        tmux set-environment -g BACKGROUND "$BACKGROUND"
        tmux source-file "$XDG_CONFIG_HOME/tmux/tmux-colors.conf"
    fi

    ls_colors="$HOME/.config/dircolors/solarized-$BACKGROUND"
    if type dircolors >/dev/null 2>&1 && [ -f "$ls_colors" ]; then
        eval "$(dircolors "$ls_colors")"
    fi
}

main